Cita APA (7th ed.)

Langan, J. (2006). English skills (8th ed.). McGraw-Hill.

Cita Chicago (17th ed.)

Langan, John. English Skills. 8th ed. Boston: McGraw-Hill, 2006.

Cita MLA (9th ed.)

Langan, John. English Skills. 8th ed. McGraw-Hill, 2006.